A water craft, such as a surfboard, particularly one on which a person stands, kneels or sits, when traversing water or riding a wave, generally has at least one fin in an underside of the water craft, generally near the tail end of the water craft. Such fins have a number of functions, including: enabling the craft to travel in a desired direction; facilitating the turning of the craft; preventing the craft from slipping sideways; and providing greater control over the movement of the craft, such as when riding a wave.
The following discussion is directed mainly to surfboards but it is to be understood that the discussion applies equally to other water craft (and surf craft) which are adapted to include fins, such as sail boards, paddle boards, rescue boards, surf skis, kayaks, and the like.
Some surfboards have fins integrally formed in the underside of the surfboard and, historically, most surfboards included such integrally formed fins. These integrally formed fins are generally ‘glassed in’, meaning that they are formed as part of the surfboard by means of fiber-reinforced resin. The formation of such ‘glassed in’ fins is quite labour intensive and it makes the subsequent sanding and finishing of the board more difficult.
In the last twenty years or so, it has become more common for surfboards to incorporate fin systems which include removable fins. Such fin systems have numerous benefits, including: enabling the fins to be removed whilst travelling; allowing damaged fins to be easily replaced; and enabling fins of different shapes or styles to be selectively used. These fin systems typically include at least one fin plug embedded in the underside of the surfboard, adapted to receive at least one surfboard fin. Each such fin plug will generally include an open cavity adapted to receive a base portion (or base element) of a surfboard fin. The fin is then able to be removably attached to the surfboard by inserting the relevant base portion (or base element) of the fin into the cavity (or cavities) of the fin plug (or fin plugs). There are numerous known fin systems which incorporate such an arrangement.
One known and commonly used fin system is described in U.S. Pat. No. 5,464,369 in the name of Fin Control Systems Pty Ltd. This system includes fins, each having two projecting base elements (or tabs) and, for each fin, two fin plugs installed in the underside of the surfboard. Each of the fin plugs has a cavity for receiving one of the base elements. Each fin plug also includes a grub screw for securing the base element within the cavity of the fin plug.
The above fin system of U.S. Pat. No. 5,464,369 has become exceedingly popular and widely used as the system enables fins to be affixed to a surfboard in a highly secure manner whilst also enabling the fins to be easily removed from the surfboard when desired. However, one drawback of the abovementioned system is that the installation and removal of fins from the fin plugs is somewhat time-consuming and requires the use of a tool (e.g. an Allen key) as the grub screws need to be threaded into or out of each cavity in order to secure or release the base elements of each fin as desired).
Another fin plug which functions in a similar way to that described above is the fin plug assembly described in PCT/AU/2008/001132, also in the name of Fin Control Systems Pty Ltd. The fin plug described in PCT/AU/2008/001132 includes two open cavities adapted to receive corresponding base elements of a surfboard fin. These base elements are adapted to be secured and released by means of grub screws (which can be threaded into or out of the cavities). Each such grub screw is adapted to press laterally against a side of a base element of the fin to secure it in position.
Other known fin systems include systems which incorporate a single fin plug, with a single cavity, for each surfboard fin. Typically, such a fin system has quite a large fin plug with an elongated fin cavity for receiving the base element(s) of a fin. In such fin systems it is again usual for each fin to be secured to the surfboard (that is, the base element of the fin to be secured within the cavity of the fin plug) by means of a grub screw arrangement, such as that mentioned above.
There is a present need for a surfboard fin plug adapted to enable surfboard fins to be removably secured to the underside of a surfboard in a quick, easy and secure manner and preferably without the need for using a tool.
The present invention is directed towards ameliorating at least some of the above described problems associated with prior art fin plugs. More particularly, the present invention is directed towards a fin plug adapted to receive a surfboard fin which enables the fin to be easily and quickly secured to or removed from a surfboard. Even more particularly, the present invention is directed towards a fin plug, adapted to receive a surfboard fin, which enables the fin to be easily and quickly secured to or removed from a surfboard without the use of a tool.
Further, the present invention is directed towards fins or other items which are adapted to be easily and quickly secured to or removed from the abovementioned fin plugs without the use of a tool.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date:                a) part of the common general knowledge; or        b) known to be relevant to an attempt to solve any problem with which this specification is concerned.        
Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application.